This invention relates to tools and more particularly, to an improved wrench which is adjustable to fit completely around any size of nut, bolt or the like.
Conventional adjustable wrenches utilize a pair of jaws which contact only two sides of a nut or a bolt, thereby making the wrench prone to slipping during use. Such wrenches also allow too much play due to the adjustment mechanisms used therein. Slippage during use can cause injury to the user's knuckles or other part of the hands. In an effort to overcome such problems, adjustable wrenches which grip nuts and bolts on all sides, also known as "box wrenches," have been developed. However, current box wrenches often still allow too much play, thereby losing their grip or lock on a nut or bolt during use.
Thus, there exists a need for an improved adjustable box wrench that eliminates play and provides a non-slip grip or lock on bolts and nuts which are not provided by current box wrenches.
The most pertinent prior art includes the following patents:
______________________________________ Patent No. (U.S. unless stated otherwise) Inventor Issue Date ______________________________________ 390,422 White Oct. 2, 1888 4,766,786 Jeremic Aug. 30 1988 Des.239,759 Glantz May 4, 1976 4,987,805 Ejdenwik Jan. 29, 1991 Swed.60657 March 11, 1923 Des.313,925 Cone Jan. 22, 1991 Des.322,545 Cone Dec. 24, 1991 3,204,497 Dinkler Sept. 7, 1965 717,390 Gray Dec. 30, 1902 Des.303,916 Colvin Oct. 10, 1989 Des.304,669 Boyd et al. Nov. 21, 1989 4,967,613 Cone Nov. 6, 1990 ______________________________________
The White patent teaches an adjustable box wrench with a gripping jaw which uses a thumb nut on a screw rod as the adjustment mechanism. The Jeremic patent discloses an adjustable wrench with a removable key adjustment mechanism. The Glantz patent shows an adjustable ring spanner for a wrench. The Ejdenwik patent discloses an adjustable wrench with a box end different from the present invention. The Swedish patent shows a wrench with an adjustable box end. The two Cone design patents show adjustable box wrenches with gripping ends. The Dinkler patent teaches a double ended adjustable box wrench. The Gray patent discloses a double-ended adjustable wrench. The Colvin patent shows another double ended adjustable box wrench with a different gripping head than the present invention. The Cone utility patent teaches an adjustable box wrench that requires a large aperture in the jaw slot into which the thumb wheel screw and the threaded adjustment rod must fit. Thus, as designed the adjustment mechanism of the Cone patent allows considerable play in the adjustment mechanism, making it susceptible to slippage during use.
Although the prior art contains many patented box wrenches, none has the same structure as the present invention which provides the benefits of the present invention as is described and illustrated herein.